( function () {

  THREE.MeshLine = function () {

    this.positions = [];

    this.previous = [];
    this.next = [];
    this.side = [];
    this.width = [];
    this.indices_array = [];
    this.uvs = [];
    this.counters = [];
    this.geometry = new THREE.BufferGeometry();

    this.widthCallback = null;

  }

  THREE.MeshLine.prototype.setGeometry = function ( g, c ) {

    this.widthCallback = c;

    this.positions = [];
    this.counters = [];

    if ( g instanceof THREE.Geometry ) {
      for ( var j = 0; j < g.vertices.length; j++ ) {
        var v = g.vertices[ j ];
        var c = j / g.vertices.length;
        this.positions.push( v.x, v.y, v.z );
        this.positions.push( v.x, v.y, v.z );
        this.counters.push( c );
        this.counters.push( c );
      }
    }

    if ( g instanceof THREE.BufferGeometry ) {
      // read attribute positions ?
    }

    if ( g instanceof Float32Array ||  g instanceof Array ) {
      for ( var j = 0; j < g.length; j += 3 ) {
        var c = j / g.length;
        this.positions.push( g[ j ], g[ j + 1 ], g[ j + 2 ] );
        this.positions.push( g[ j ], g[ j + 1 ], g[ j + 2 ] );
        this.counters.push( c );
        this.counters.push( c );
      }
    }

    this.process();

  }

  THREE.MeshLine.prototype.compareV3 = function ( a, b ) {

    var aa = a * 6;
    var ab = b * 6;
    return ( this.positions[ aa ] === this.positions[ ab ] ) && ( this.positions[ aa + 1 ] === this.positions[ ab + 1 ] ) && ( this.positions[ aa + 2 ] === this.positions[ ab + 2 ] );

  }

  THREE.MeshLine.prototype.copyV3 = function ( a ) {

    var aa = a * 6;
    return [ this.positions[ aa ], this.positions[ aa + 1 ], this.positions[ aa + 2 ] ];

  }

  THREE.MeshLine.prototype.process = function () {

    var l = this.positions.length / 6;

    this.previous = [];
    this.next = [];
    this.side = [];
    this.width = [];
    this.indices_array = [];
    this.uvs = [];

    for ( var j = 0; j < l; j++ ) {
      this.side.push( 1 );
      this.side.push( -1 );
    }

    var w;
    for ( var j = 0; j < l; j++ ) {
      if ( this.widthCallback ) w = this.widthCallback( j / ( l - 1 ) );
      else w = 1;
      this.width.push( w );
      this.width.push( w );
    }

    for ( var j = 0; j < l; j++ ) {
      this.uvs.push( j / ( l - 1 ), 0 );
      this.uvs.push( j / ( l - 1 ), 1 );
    }

    var v;

    if ( this.compareV3( 0, l - 1 ) ) {
      v = this.copyV3( l - 2 );
    } else {
      v = this.copyV3( 0 );
    }
    this.previous.push( v[ 0 ], v[ 1 ], v[ 2 ] );
    this.previous.push( v[ 0 ], v[ 1 ], v[ 2 ] );
    for ( var j = 0; j < l - 1; j++ ) {
      v = this.copyV3( j );
      this.previous.push( v[ 0 ], v[ 1 ], v[ 2 ] );
      this.previous.push( v[ 0 ], v[ 1 ], v[ 2 ] );
    }

    for ( var j = 1; j < l; j++ ) {
      v = this.copyV3( j );
      this.next.push( v[ 0 ], v[ 1 ], v[ 2 ] );
      this.next.push( v[ 0 ], v[ 1 ], v[ 2 ] );
    }

    if ( this.compareV3( l - 1, 0 ) ) {
      v = this.copyV3( 1 );
    } else {
      v = this.copyV3( l - 1 );
    }
    this.next.push( v[ 0 ], v[ 1 ], v[ 2 ] );
    this.next.push( v[ 0 ], v[ 1 ], v[ 2 ] );

    for ( var j = 0; j < l - 1; j++ ) {
      var n = j * 2;
      this.indices_array.push( n, n + 1, n + 2 );
      this.indices_array.push( n + 2, n + 1, n + 3 );
    }

    if ( !this.attributes ) {
      this.attributes = {
        position: new THREE.BufferAttribute( new Float32Array( this.positions ), 3 ),
        previous: new THREE.BufferAttribute( new Float32Array( this.previous ), 3 ),
        next: new THREE.BufferAttribute( new Float32Array( this.next ), 3 ),
        side: new THREE.BufferAttribute( new Float32Array( this.side ), 1 ),
        width: new THREE.BufferAttribute( new Float32Array( this.width ), 1 ),
        uv: new THREE.BufferAttribute( new Float32Array( this.uvs ), 2 ),
        index: new THREE.BufferAttribute( new Uint16Array( this.indices_array ), 1 ),
        counters: new THREE.BufferAttribute( new Float32Array( this.counters ), 1 )
      }
    } else {
      this.attributes.position.copyArray( new Float32Array( this.positions ) );
      this.attributes.position.needsUpdate = true;
      this.attributes.previous.copyArray( new Float32Array( this.previous ) );
      this.attributes.previous.needsUpdate = true;
      this.attributes.next.copyArray( new Float32Array( this.next ) );
      this.attributes.next.needsUpdate = true;
      this.attributes.side.copyArray( new Float32Array( this.side ) );
      this.attributes.side.needsUpdate = true;
      this.attributes.width.copyArray( new Float32Array( this.width ) );
      this.attributes.width.needsUpdate = true;
      this.attributes.uv.copyArray( new Float32Array( this.uvs ) );
      this.attributes.uv.needsUpdate = true;
      this.attributes.index.copyArray( new Uint16Array( this.indices_array ) );
      this.attributes.index.needsUpdate = true;
    }

    this.geometry.addAttribute( 'position', this.attributes.position );
    this.geometry.addAttribute( 'previous', this.attributes.previous );
    this.geometry.addAttribute( 'next', this.attributes.next );
    this.geometry.addAttribute( 'side', this.attributes.side );
    this.geometry.addAttribute( 'width', this.attributes.width );
    this.geometry.addAttribute( 'uv', this.attributes.uv );
    this.geometry.addAttribute( 'counters', this.attributes.counters );

    this.geometry.setIndex( this.attributes.index );

  }

  function memcpy( src, srcOffset, dst, dstOffset, length ) {
    var i

    src = src.subarray || src.slice ? src : src.buffer
    dst = dst.subarray || dst.slice ? dst : dst.buffer

    src = srcOffset ? src.subarray ?
      src.subarray( srcOffset, length && srcOffset + length ) :
      src.slice( srcOffset, length && srcOffset + length ) : src

    if ( dst.set ) {
      dst.set( src, dstOffset )
    } else {
      for ( i = 0; i < src.length; i++ ) {
        dst[ i + dstOffset ] = src[ i ]
      }
    }

    return dst
  }

  /**
   * Fast method to advance the line by one position.  The oldest position is removed.
   * @param position
   */
  THREE.MeshLine.prototype.advance = function ( position ) {

    var positions = this.attributes.position.array;
    var previous = this.attributes.previous.array;
    var next = this.attributes.next.array;
    var l = positions.length;

    // PREVIOUS
    memcpy( positions, 0, previous, 0, l );

    // POSITIONS
    memcpy( positions, 6, positions, 0, l - 6 );

    positions[ l - 6 ] = position.x;
    positions[ l - 5 ] = position.y;
    positions[ l - 4 ] = position.z;
    positions[ l - 3 ] = position.x;
    positions[ l - 2 ] = position.y;
    positions[ l - 1 ] = position.z;

    // NEXT
    memcpy( positions, 6, next, 0, l - 6 );

    next[ l - 6 ] = position.x;
    next[ l - 5 ] = position.y;
    next[ l - 4 ] = position.z;
    next[ l - 3 ] = position.x;
    next[ l - 2 ] = position.y;
    next[ l - 1 ] = position.z;

    this.attributes.position.needsUpdate = true;
    this.attributes.previous.needsUpdate = true;
    this.attributes.next.needsUpdate = true;

  };

  THREE.MeshLineMaterial = function ( parameters ) {

    var vertexShaderSource = [
'precision highp float;',
'',
'attribute vec3 position;',
'attribute vec3 previous;',
'attribute vec3 next;',
'attribute float side;',
'attribute float width;',
'attribute vec2 uv;',
'attribute float counters;',
'',
'uniform mat4 projectionMatrix;',
'uniform mat4 modelViewMatrix;',
'uniform vec2 resolution;',
'uniform float lineWidth;',
'uniform vec3 color;',
'uniform float opacity;',
'uniform float near;',
'uniform float far;',
'uniform float sizeAttenuation;',
'',
'varying vec2 vUV;',
'varying vec4 vColor;',
'varying vec3 vPosition;',
'varying float vCounters;',
'',
'vec2 fix( vec4 i, float aspect ) {',
'',
'    vec2 res = i.xy / i.w;',
'    res.x *= aspect;',
'	 vCounters = counters;',
'    return res;',
'',
'}',
'',
'void main() {',
'',
'    float aspect = resolution.x / resolution.y;',
'	 float pixelWidthRatio = 1. / (resolution.x * projectionMatrix[0][0]);',
'',
'    vColor = vec4( color, opacity );',
'    vUV = uv;',
'',
'    mat4 m = projectionMatrix * modelViewMatrix;',
'    vec4 finalPosition = m * vec4( position, 1.0 );',
'    vec4 prevPos = m * vec4( previous, 1.0 );',
'    vec4 nextPos = m * vec4( next, 1.0 );',
'',
'    vec2 currentP = fix( finalPosition, aspect );',
'    vec2 prevP = fix( prevPos, aspect );',
'    vec2 nextP = fix( nextPos, aspect );',
'',
'	 float pixelWidth = finalPosition.w * pixelWidthRatio;',
'    float w = 1.8 * pixelWidth * lineWidth * width;',
'',
'    if( sizeAttenuation == 1. ) {',
'        w = 1.8 * lineWidth * width;',
'    }',
'',
'    vec2 dir;',
'    if( nextP == currentP ) dir = normalize( currentP - prevP );',
'    else if( prevP == currentP ) dir = normalize( nextP - currentP );',
'    else {',
'        vec2 dir1 = normalize( currentP - prevP );',
'        vec2 dir2 = normalize( nextP - currentP );',
'        dir = normalize( dir1 + dir2 );',
'',
'        vec2 perp = vec2( -dir1.y, dir1.x );',
'        vec2 miter = vec2( -dir.y, dir.x );',
'        //w = clamp( w / dot( miter, perp ), 0., 4. * lineWidth * width );',
'',
'    }',
'',
'    //vec2 normal = ( cross( vec3( dir, 0. ), vec3( 0., 0., 1. ) ) ).xy;',
'    vec2 normal = vec2( -dir.y, dir.x );',
'    normal.x /= aspect;',
'    normal *= .5 * w;',
'',
'    vec4 offset = vec4( normal * side, 0.0, 1.0 );',
'    finalPosition.xy += offset.xy;',
'',
'	 vPosition = ( modelViewMatrix * vec4( position, 1. ) ).xyz;',
'    gl_Position = finalPosition;',
'',
'}' ];

    var fragmentShaderSource = [
		'#extension GL_OES_standard_derivatives : enable',
'precision mediump float;',
'',
'uniform sampler2D map;',
'uniform float useMap;',
'uniform float useDash;',
'uniform vec2 dashArray;',
'uniform float visibility;',
'uniform float alphaTest;',
'',
'varying vec2 vUV;',
'varying vec4 vColor;',
'varying vec3 vPosition;',
'varying float vCounters;',
'',
'void main() {',
'',
'    vec4 c = vColor;',
'	 if( c.a < alphaTest ) discard;',
'    if( useMap == 1. ) c *= texture2D( map, vUV );',
'	 if( useDash == 1. ){',
'	 	 ',
'	 }',
'    gl_FragColor = c;',
'	 gl_FragColor.a *= step(vCounters,visibility);',
'}' ];

    function check( v, d ) {
      if ( v === undefined ) return d;
      return v;
    }

    THREE.Material.call( this );

    parameters = parameters ||  {};

    this.lineWidth = check( parameters.lineWidth, 1 );
    this.map = check( parameters.map, null );
    this.useMap = check( parameters.useMap, 0 );
    this.color = check( parameters.color, new THREE.Color( 0xffffff ) );
    this.opacity = check( parameters.opacity, 1 );
    this.resolution = check( parameters.resolution, new THREE.Vector2( 1, 1 ) );
    this.sizeAttenuation = check( parameters.sizeAttenuation, 1 );
    this.near = check( parameters.near, 1 );
    this.far = check( parameters.far, 1 );
    this.dashArray = check( parameters.dashArray, [] );
    this.useDash = ( this.dashArray !== [] ) ? 1 : 0;
    this.visibility = check( parameters.visibility, 1 );
    this.alphaTest = check( parameters.alphaTest, 0 );

    var material = new THREE.RawShaderMaterial( {
      uniforms: {
        lineWidth: { type: 'f', value: this.lineWidth },
        map: { type: 't', value: this.map },
        useMap: { type: 'f', value: this.useMap },
        color: { type: 'c', value: this.color },
        opacity: { type: 'f', value: this.opacity },
        resolution: { type: 'v2', value: this.resolution },
        sizeAttenuation: { type: 'f', value: this.sizeAttenuation },
        near: { type: 'f', value: this.near },
        far: { type: 'f', value: this.far },
        dashArray: { type: 'v2', value: new THREE.Vector2( this.dashArray[ 0 ], this.dashArray[ 1 ] ) },
        useDash: { type: 'f', value: this.useDash },
        visibility: { type: 'f', value: this.visibility },
        alphaTest: { type: 'f', value: this.alphaTest }
      },
      vertexShader: vertexShaderSource.join( '\r\n' ),
      fragmentShader: fragmentShaderSource.join( '\r\n' )
    } );

    delete parameters.lineWidth;
    delete parameters.map;
    delete parameters.useMap;
    delete parameters.color;
    delete parameters.opacity;
    delete parameters.resolution;
    delete parameters.sizeAttenuation;
    delete parameters.near;
    delete parameters.far;
    delete parameters.dashArray;
    delete parameters.visibility;
    delete parameters.alphaTest;

    material.type = 'MeshLineMaterial';

    material.setValues( parameters );

    return material;

  };

  THREE.MeshLineMaterial.prototype = Object.create( THREE.Material.prototype );
  THREE.MeshLineMaterial.prototype.constructor = THREE.MeshLineMaterial;

  THREE.MeshLineMaterial.prototype.copy = function ( source ) {

    THREE.Material.prototype.copy.call( this, source );

    this.lineWidth = source.lineWidth;
    this.map = source.map;
    this.useMap = source.useMap;
    this.color.copy( source.color );
    this.opacity = source.opacity;
    this.resolution.copy( source.resolution );
    this.sizeAttenuation = source.sizeAttenuation;
    this.near = source.near;
    this.far = source.far;

    return this;

  };

} )();
